Random orbital sanders are well known and generally comprise a motor for driving a balanced shaft for rotational movement about a first or driven axis, and a bearing device for coupling a sanding pad or disc to the balanced shaft for rotational movement relative thereto about a second axis disposed in an offset or parallel relation to the first axis. During operation of this type of sander, the sanding pad is forced to move along a circular path disposed concentrically of or to orbit relative to the first axis, while being free to rotate relative to the second axis.
Prior random orbital sanders suffer from a common practical drawback, namely, the relatively short useful life span of the bearing devices employed to rotationally couple their balanced shafts and sanding pads as a result of ingestion of abrasive materials to which they are exposed during use.